Your right, EA will not struggle at all with sales of any of their game titles even though they have pulled the plug from Game. There are many other online and retail places which will still stock EA games, this will not hurt EA at all
Of course it will.
The are going to lose the bulk of their sales that could have been made through GAME and Gamestation both online and off.
Most of the people who shop in store do so because they find it convenient and familiar. They're not going to go online because they don't want to.
Most people who shop in store do so because it's quick and simple and while a small minority might clench their fists and stare meaningfully into the distance as they contemplate the full reprecussions of what this could mean for GAME... for EA... for gamers in general...
Most of these people won't even care or notice that there has been a spat between a major high street chain and a publisher. They will go to shop and not buy EA's latest Flagship title because it is not available to be sold.
EA lose money and potentially a large amount because the only way around this loss would be to sell the same amount of the Pie they cut out of their profits by cutting out GAME and Gamestation from their list of distributing retailers.
Sure some people will figure out that they can get it somewhere else but not enough will do so on this occasion to avoid a loss.